Biomedical subjects

T Ishitake

Publications and source records attributed to T Ishitake.

11 recordsLinked to original sources

PubMed1998

Whole-body vibration suppresses gastric motility in healthy men.

The influence of whole-body vibration on gastric motility was investigated by using an electrogastrography (EGG) in seven healthy men. The EGG is usually referred to as a noninvasive technique of recording gastric myoelectrical activity by means of placing electrodes on the abdominal surface. Sinusoidal vertical vibration at each of 3 different frequencies (10 Hz, 20 Hz, 40 Hz) were randomly given to the subject seated on a platform of vibrator for 5 min. The vibration magnitude was kept at a constant of 2.0 msec-2 (r.m.s.) during operation. The mean dominant frequency of EGG at control period was prior to operation 3.3 cycles per min (cpm). During vibration exposure at 10 Hz, the peak of dominant frequency increased to 3.9 cpm, and the relative power of slow wave showed the statistically significant decrease (45.8%, p < 0.05). The mean relative power of slow wave which is composed of frequencies ranged from 2.0 to 5.0 cpm was 56.6% at control period. On the contrary the mean relative power of frequencies ranging from 5.0 to 9.0 cpm, tachygastria increased from 29.5% to 39.1%. These results suggest that the short-term exposure to whole-body vibration effects on the gastric myoelectrical activity.

Adult↗

PubMed1998

Changes of visual performance induced by exposure to whole-body vibration.

To clarify the effects of whole-body vibration (WBV) on visual performance, visual acuity and a self-rated assessment of difficulties in visible perception were determined after various frequencies of vibration in six healthy males. Two different sitting postures, an erect posture and a muscle-relaxed posture, were used. Sinusoidal vertical vibrations at ten frequencies (8, 10, 12.5, 16, 20, 25, 31.5, 40, 63.5 and 80 Hz) were applied to the seated subjects for 20 sec. The magnitude of acceleration at each vibration frequency was maintained at 2.5 msec-2 (r.m.s.). The visual performance was evaluated by a standard visual acuity test and a self-rated assessment for difficulties in visible perception. The disturbances of visual performance were dependent on the vibration frequency (p < 0.01, ANOVA) with a maximum reduction of visual acuity at a frequency of 12.5 Hz. The disruption of the visual performance was more severe with the erect posture than with the muscle-relaxed posture. In conclusion, short-term WBV exposure can affect visual performance, depending on the vibration frequency and the sitting posture. The visual acuity and self-rated assessment of disturbances of vision may be influenced by the resonance frequency of the eyeball.

Adult↗

PubMed1996

A revised cold water immersion test for assessing peripheral circulatory function.

To improve the conventional cold water immersion test for assessing peripheral circulatory function, the immersed area of the hand was changed in this study. Twenty-seven healthy medical students with a mean age of 24 years participated in the study. The cold water immersion tests were carried out using two methods (in 5 degree C water for 1 min), in which the immersed area was up to the metacarpophalangeal (MP) joints (hereafter, MP-method) which is a new method, or to the wrist (hereafter, W-method) which is a conventional method. The recovery of skin temperature, vibratory perception threshold and complaints of finger pain were determined during cold immersion tests with the two methods. The mean skin temperature for the MP-method after immersion recovered more quickly than that for the W-method. However, the time courses of recovering were parallel for the two methods. Significant differences were noted at 3 min, 5 min and 10 min after cessation of immersion. There was a significant positive correlation in the recovery rates at 5 min after immersion between the two methods (correlation coefficient = 0.65, p < 0.01). The mean vibratory thresholds for the W-method were higher than those for the MP-method, and the difference was significant (p < 0.01). All subjects preferred the MP-method to the W-method because there was less finger pain. These results indicate that the MP-method, immersion up to the MP joint of a hand, for assessing peripheral circulatory function is better than the W-method.

Adult↗

PubMed1995

Application of Stockholm criteria to patients with hand-arm vibration syndrome in a follow-up study.

We applied Stockholm criterion to patients with hand-arm vibration syndrome (HAVS) for assessing the therapeutic effects in comparison with the criterion of the Ministry of Labour in Japan (MLJ). Forty male patients recognized as an occupational disease were examined in two times (mean interval periods 3.0 years). The subjects were free from vibratory tasks during the mean period of 8.3 years. The clinical examinations and some laboratory tests were conducted with the same procedures by the two same occupational physicians. The criterion of MLJ was graded more severe than Stockholm one for the vascular component at the first examination. According to Stockholm criterion, 16 patients (40%) were classified into stage 0 in the vascular component, 11 (70%) of which complained of coldness in the fingers. At the second examination, 9 of 16 patients in stage 0 had Raynaud's phenomenon (RP). On the other hand, the criterion of MLJ could reflect an improvement of symptoms, for example, coldness. The findings may indicate that Stockholm criterion for vascular component is not enough to assess the clinical changes for light stages according to the severity of RP alone. For the sensorineural (SN) component, both criteria were almost compatible. From the viewpoint of preventive medicine, it was concluded that Stockholm criterion was not suitable for evaluating their clinical severity in the early stage of HAVS.

Disability Evaluation↗

PubMed1995

A new criterion proposed for the diagnosis of hand-arm vibration syndrome.

To propose a new criterion for the diagnosis of hand-arm vibration syndrome (HAVS), we evaluated the severity of the patients in comparison with the criterion of the Ministry of Labour in Japan (MLJ) and the Stockholm criterion. The characteristics of the Stockholm criterion was to classify severe cases with vascular disorders, because of evaluation due to the frequency of Raynaud's phenomenon alone. The Stockholm criterion diagnosed the HAVS separately in vascular and sensorineural disorders. The MLJ criterion was able to subdivide light stages. In vascular disorders, the MLJ criterion made serious consideration about cold sensation which appeared long before the occurrence of Raynaud's phenomenon. The MLJ criterion diagnosed the patients with vascular, sensorineural and motor (musculoskeletal) system disorders comprehensively. A new criterion which we proposed includes sensorineural, vascular and motor system disorders, the grade of which is evaluated in each system. The diagnosis might be done comprehensively.

Cold Temperature↗

PubMed1994

[Perceived health of persons and their practice of health promoting activities].

The perceived health of persons and their practice of health promoting activities were surveyed using a self-rating questionnaire with 49 items assessing level of health, practice of health promoting activities, life styles, health education, and participation in health screening for general health conditions and cancers. The questionnaires were mailed to 2,500 residents of a city, aged from 30 to 69 years old, randomly selected according to the composition ratios of the populations in the city. Persons from 2,333 subjects (1,057 male and 1,276 female) were effectively collected, representing about 1% of the city's population. General health was good in about 85% of the subjects, with decreases observed with age. Practice of activities for health promotion was wide-spread among the subjects. These activities included regularity, diet, nutrition, smoking and drinking control, physical exercise, sleep, and rest. The subjects expressed strong fear of cancers and concerns about deterioration in physical fitness. Their target life style was one with adequate sleep and rest, regularity in eating, good nutrition, and avoidance of overwork. Health screening participation rates were low at approximately 28% because of their perceived good health, and busy daily life and work. It appears that the perceived health of citizens may not always correlated with the practice of health promoting activities.

Adult↗

PubMed1993

[Difference in perceived health between blue- and white-collar workers of a manufacturing factory by a self-administered questionnaire].

In order to examine the differences in which blue- and white-collar workers perceive their own health status, a survey using self-administered questionnaire was conducted. The subjects were 1,428 male workers in a tire manufacturing factory, consisting of 1,185 blue-collar workers and 243 white-collar workers. Most of the blue-collar workers were engaged in shift work consisting of three shifts/d. The questionnaire included 32 items concerning health habits, life and job satisfaction, mental stress, and type A behavior. The following findings were obtained. Good daily health habits were related to age. Older workers had better health habits than the younger ones both in white- and blue-collar workers. The white-collar workers were more satisfied with their life and jobs, and also showed type A behaviors at a higher rate. As for fatigue and dissatisfaction association with shift work, the workers' complaints increased in the order of day shift, evening shift and midnight shift. The older workers had fewer complaints than the younger ones. These results suggested that health management and education will be more effective if the working conditions and the background of each worker are taken into consideration.

Adult↗

PubMed1992

[A 4 degrees C-1 min method of cold water immersion test for peripheral circulatory function in fingers].

To assess the validity of a new simplified cold water immersion test (4 degrees C-1 min method) for peripheral circulatory function, comparison was made with the conventional method (10 degrees C-10 min method). These two different methods of cold immersion test were applied to 23 patients with vibration disease and 24 healthy men. Observation was made on finger skin temperature by a thermistor and complaints in the hand by a 5-step self-reported scale method every minute during the test. The patterns of recovery of skin temperature after cold immersion in each group were similar in both methods. Pain in the hand in the 4 degrees C-1 min method was less than that in the 10 degrees C-10 min method. The recovery rate at 5 min in the patients with Raynaud's phenomenon was lower than that in those without Raynaud's phenomenon in the 4 degrees C-1 min method (p < 0.01). However, no significant differences were noted in 10 degrees C-10 min method. The results suggest that the new method is feasible in detecting the response of vasodilation after immersion. In the recovery rate at 5 min after immersion, near values of the sensitivity and specificity were observed between 50% cut-off values in the 4 degrees C-1 min method and 30% value in the 10 degrees C-10 min method. Thus, the 4 degrees C-1 min method is considered to be more useful to evaluate the physiological response after cold immersion than the 10 degrees C-10 min method.

Adult↗

PubMed1990

Hemodynamic changes in skin microcirculation induced by vibration stress in the conscious rabbit.

Cutaneous microcirculatory responses to vibration stress were observed by microphotoelectric plethysmography in a transparent round window installed in the ears of conscious rabbits. Vertical vibrations at frequencies ranging from 8 to 250 Hz were applied to the abdomen of the rabbits for 5 min. The vibrations produced an increase in heart rate and the index of discomfort, and a decrease in blood flow in the skin microcirculation. The maximum response was observed at 63 Hz. Rhythmic fluctuations in microcirculation were associated with two components: component A had a small amplitude and high frequency, and component B had a large amplitude and low frequency. Vibration exposure led to a large increase in component B and a smaller increase in component A. During vibration exposure, component A was suppressed by treatment with diltiazem, a calcium channel blocker, and was not affected by bunazosin, an alpha-1 adrenoceptor antagonist. The opposite changes were observed for component B. This indicates that components A and B of the rhythmic fluctuations are regulated by myogenic and neurogenic activities, respectively. Thus, the hemodynamic changes of skin microcirculation induced by vibration may actually be due to a neurogenic factor, especially sympathetic nerve activity. The responses appear to depend on the frequency of the vibrations.

Animals↗

PubMed1990

Cardiovascular reflexes during vibration stress.

Vibration disease due to hand-held vibratory tools has various symptoms and signs which can be characterized by the severity. They include disorders of the central and autonomic nervous systems, as well as peripheral system disorders. The mechanism of Raynaud's phenomenon in vibration disease is proposed to be: Vibration and cold affect the local vessels and nerves directly, leading to enhanced release of chemical vasoconstrictors. Vibration, noise, cold, ergonomic and biodynamic conditions, and emotional stress during work result in disorders of the central and autonomic nervous systems. In the early stages, the autonomic nervous system may be stimulated, and in the later stages it is suppressed. When local vessel injuries and disorders of the central and local autonomic nervous mechanisms controlling the vessels occur, vasospasms in the fingers develop when the whole body is exposed to cold. The cardiovascular system, other than the peripheral circulatory system, may adapt to vibration stress. The adaptation subsides 7 to 8 years after discontinuation of the use of hand-held vibratory tools.

Cardiovascular System↗

PubMed1989

Frequency dependence of the suppressive effects of vibration on atherosclerosis in the rabbit.

Whole-body vibration suppresses the development of atherosclerosis in the rabbit (Oki and Matoba, 1987). The present study was designed to clarify whether the effect of vibration on atherosclerosis depends on the frequency of vibration. Longitudinal vibrations at a frequency of 30 or 60 Hz was applied to 12 New Zealand white rabbits for 12 weeks. The gradual decrease in body weight and blood hematocrit in the vibration groups with time were parallel to the changes in the controls. The rate of increase in serum lipid concentrations induced by a cholesterol-rich diet was significantly suppressed in the vibration groups, as compared to the controls. This may be due to the vibration and not the diet. The aortic wall was thinner at 60 Hz than at 30 Hz, whereas the ratios of trace metals (Ca/Mg and Zn/Cu) in the aortic tissues were smaller at 30 Hz. The area of plaque formation in the intima was smaller at 60 Hz than at 30 Hz (p less than 0.05). Thus, the suppressive effect of vibration on the development of atherosclerosis in the aorta may be greater at a frequency of 60 Hz than at 30 Hz. Vibration may play an important role in lipid metabolism.

Animals↗